"Three-dimensional mammography addresses the two major flaws of mammography," she says. One is the inability to see some cancers on a mammogram. The other is a need to call back women for what looks like abnormal tissue that isn't, she says.

The study is published in the journal Radiology. Hologic, the maker of the 3-D system studied, funded the study as part of the process to receive FDA approval for the test, Rafferty says. She does not work for Hologic.

The FDA approved the 3-D system in early 2011. It is now installed in more than 300 centers, according to Jim Culley, a spokesman for Hologic.

More About 3-D Imaging

Rafferty says using 3-D is helpful for routine screening and for high-risk women.

A conventional digital mammogram is only two-dimensional. It produces a single, flattened image.

The 3-D system captures multiple images from different angles around the breast. It helps give the radiologist clearer views through overlapping breast tissue.

A woman having both types is not likely to notice any difference, as both digital and 3-D mammograms can be done on the same equipment.

3-D Plus Conventional: Study Results

Women in the study received mammograms at five different sites between July 2006 and May 2007. Of the 997 women eligible, complete analysis was done on 622.

Each had a digital mammogram and a 3-D mammogram.

The rate at which cancer was correctly identified increased by up to 16% by adding the use of 3-D. That means ''as many as 16% more cancers will be found," Rafferty says.